/*
 * Copyright 2011-2012 by The Regents of the University of California Licensed
 * under the Apache License, Version 2.0 (the "License"); you may not use this
 * file except in compliance with the License. you may obtain a copy of the
 * License from
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package edu.ucsd.db.bassarisk.query.expression.visitor;

import java.util.List;

import edu.ucsd.db.bassarisk.exception.VisitorException;
import edu.ucsd.db.bassarisk.query.expression.Expressions.Expression;
import edu.ucsd.db.bassarisk.query.expression.Expressions.KeywordMatchExpr;
import edu.ucsd.db.bassarisk.query.expression.Expressions.NonterminalExpr;
import edu.ucsd.db.bassarisk.query.expression.Expressions.PositionMaxSeparation;
import edu.ucsd.db.bassarisk.query.expression.Expressions.PositionMinSeparation;
import edu.ucsd.db.bassarisk.query.expression.Expressions.PositionSeparation;
import edu.ucsd.db.bassarisk.query.expression.Expressions.PositionWindow;
import edu.ucsd.db.bassarisk.query.expression.Expressions.StructurePredExpr;
import edu.ucsd.db.bassarisk.schema.RunClass;

/**
 * Collect the set of all position-run classes mentioned by the expressions of
 * the query.
 */
public class RunClassCollectionTraversal extends
    ExpressionTreeCollectionTraversal<RunClass> {
  @Override
  public Void visitKeywordMatchExpr(final KeywordMatchExpr expr,
                                    final List<RunClass> arg)
      throws VisitorException {
    return null;
  }

  @Override
  public Void visitNonterminalExpr(final NonterminalExpr expr,
                                   final List<RunClass> arg) throws VisitorException {
    for (Expression subExpr : expr.getSubExprs()) {
      subExpr.accept(this, arg);
    }
    return null;
  }

  @Override
  public Void visitPositionMaxSeparation(final PositionMaxSeparation expr,
                                         final List<RunClass> arg)
      throws VisitorException {
    arg.add(expr.getRunClass());
    expr.getSubExpr().accept(this, arg);
    return null;
  }

  @Override
  public Void visitPositionMinSeparation(final PositionMinSeparation expr,
                                         final List<RunClass> arg)
      throws VisitorException {
    arg.add(expr.getRunClass());
    expr.getSubExpr().accept(this, arg);
    return null;
  }

  @Override
  public Void visitPositionSeparation(final PositionSeparation expr,
                                      final List<RunClass> arg)
      throws VisitorException {
    arg.add(expr.getRunClass());
    expr.getSubExpr().accept(this, arg);
    return null;
  }

  @Override
  public Void
      visitPositionWindow(final PositionWindow expr, final List<RunClass> arg)
          throws VisitorException {
    arg.add(expr.getRunClass());
    expr.getSubExpr().accept(this, arg);
    return null;
  }

  @Override
  public Void visitStructurePredExpr(final StructurePredExpr expr,
                                     final List<RunClass> arg)
      throws VisitorException {
    arg.add(expr.getRunClass());
    expr.getSubExpr().accept(this, arg);
    return null;
  }
}
